A pumping action can be achieved for a gas or liquid by disposing a piston inside a cylindrical chamber so as to be free to move reciprocally, connecting the cylindrical chamber to the outside via an inlet/outlet valve, and reciprocally moving the piston. As examples of apparatuses that use this kind of pumping action, an apparatus constructed by attaching a magnet to a piston disposed inside a cylinder, disposing an electromagnetic coil around an outside of the cylinder and causing the electromagnetic force of the electromagnetic coil to act upon and reciprocally move the piston (see Japanese Laid-Open Utility Model No. H07-4875) and a pump apparatus where cylinders are constructed as double pipes and are disposed facing one another and joined as two stages (see Japanese Laid-Open Patent Publication No. H06-159232) have been proposed.
Conventional apparatuses where an electromagnetic force acts from outside a cylindrical chamber upon a piston disposed inside the cylindrical chamber to reciprocally drive the piston are constructed so as to produce a pumping action by forming the cylinder in a long slim shape along the axial direction and providing the piston with a comparatively long stroke. Accordingly, when a small and slim pump apparatus is required, such as when a pump apparatus is used to cool a small-scale electronic appliance such as a notebook computer, there has been the problem that it is difficult to make the construction of a conventional pump apparatus compact. The reciprocal movement of the piston also tends to produce vibration and noise when the pump apparatus is driven, which is problematic for electronic appliances and the like where there are demands for reductions in vibration and quiet operation.
The present invention was conceived in view of the problems described above and it is an object of the present invention to provide an electromagnetic pump that can be effectively made smaller and slimmer, that has reduced vibration during operation, and can be favorably installed in electronic appliances and the like.